Kurt I believe the 4's are correct and believe that they are closed into 1943. I would not count the U wrong until I had further input. Sometimes there is not much logic to be applied on something that was not a science.

Kurt, the photo below shows the only UA serial number in my collection. (And the three characters I blacked out also appear authentic.) The usual 4 for 1940 Flathead and Knucklehead serial numbers had a closed top and a wide serif base. The seriffed A appears to be authentic and I’ve also seen the seriffed A in a 1940 WLA serial number, although my photo of that one is blurry. For the 1941 WLA, I have good photos showing that both the seriffed A and the sans serif A were used.

I have U-series examples for every year of their production except 1943 but the only ones that have a seriffed U are from early-1937 models. Later in the 1937 production run, H-D changed to several different stamps, including a sans serif U. So it seems unusual for a seriffed U to be in a 1940 production serial number.

But the seriffed U in your photo could just be an exception, assuming the characters you didn’t show are correct for 1940? Or it could be a replacement case stamped by a dealer who applied the wrong U. Do you know if it was a replacement case? Eric

Hello,I too have had a 40 UA for several years now. Currently not running, but hope to have her operational the middle of next year. Hopefully the image will upload properly and not display too large. Still somewhat new at this.Ed

The more I read about this stuff, the more convinced I am that there are NO DEFINATIVES regarding this situation! The #'s in the original post appear Un-Altered, but are different from other Supposed #'s that others have possession of. I think that Individual Employees had their stamp sets, and while similar, there could be MANY instances where Legitimate #'s could Vary Widely!! Anybody who has Ever Been In A Factory would knot that NOTHING is ABSOLUTE!

A hint: when linkage to an image on another site, there's a method for forcing the browser to open it on a new page (making the "back" button redundant).Instead of <a href="XXXXX.com"></a>, use <a href="XXXXX.com" target="_blank"></a>

Tom.....it's not a 4000 vin.......which is now why I know the cases are bogus, plus they don't fall in line with anything Bruce has in his Military book. And after looking at the pix I have again, the cast date on the gear case is H 7....can't read the left case.

Thanks for all of the input and replies.

Too bad about these cases....I got them from someone years ago who I thought was a reputable person in the business.....now I know better.